Endoscopic augmentation of the cardia with a biocompatible injectable polymer (Enteryx) in a porcine model.

BACKGROUND: Endoscopic approaches to restore the gastroesophageal barrier in patients with gastroesophageal reflux disease (GERD) are presently undergoing clinical trial. The aim of the study was to demonstrate the feasibility, durability, safety, and antireflux efficacy following augmentation of the cardia with a biocompatible injectable polymer (Enteryx). METHODS: Augmentation was performed in 12 Yucatan mini-pigs. The cardia was injected circumferentially with 1-1.5 ml of Enteryx at three or four sites. Four groups of three animals each were killed at 2, 6, 12, and 24 weeks following augmentation. Gastrointestinal endoscopy and esophageal manometry were performed preoperatively and postoperatively. Competency was determined as the intragastric pressure (yield pressure) and volume (yield volume) needed during gastric distension with air and water to result in equalization of gastric and esophageal pressure. Comparisons were made with a group of noninjected animals (n = 6). RESULTS: All animals had a normal eating pattern; none showed any evidence of vomiting or regurgitation. The median injection volume was 4 ml (range, 1-8). At autopsy, implants were found in 83% of the animals. Intramuscular placement of the implant was durable, whereas sloughing occurred if the implant was placed submucosally. The mechanical properties of sphincter length and pressure were unaffected by the injection. The median yield pressure of the animals that survived for >6 weeks (21.4 mmHg) was significantly greater (p = 0.049) than the animals that survived for <6 weeks (4.5 mmHg) and greater (p = 0.054) than the control animals (9.1 mmHg), suggesting that the healing process was associated with reduced distensibility of the cardia. CONCLUSIONS: Augmentation of the cardia with an injectable polymer (Enteryx) is simple, safe, and durable. Early studies suggest that alteration in the distensibility and geometry of the gastroesophageal junction may provide antireflux protection.

5-year incidence of adenomas after negative colonoscopy in asymptomatic average-risk persons [see comment].

BACKGROUND & AIMS: Cost-effectiveness of colorectal cancer screening will be maximized by selecting the widest screening intervals that effectively prevent cancer mortality. However, data on the incidence of neoplasia in persons with no abnormal findings on initial examination are limited. The aim of this study was to describe the incidence of colonic neoplasia 5 years after negative screening colonoscopy in asymptomatic average-risk persons. METHODS: We previously reported the results of screening colonoscopy in 496 asymptomatic average-risk persons, 368 of whom had no neoplasia identified. Colonoscopy to the cecum was performed in 154 of these persons at a mean of 66 months after the initial negative colonoscopy. RESULTS: Forty-one (27%) had at least one adenoma, but only 1 person had an adenoma > or = 1 cm and none had cancer, severe dysplasia, or villous or tubulovillous histology. Hyperplastic polyps at the initial examination did not predict incident adenomas. Regular nonsteroidal anti-inflammatory drug use was associated with a decreased rate of incident adenomas. CONCLUSIONS: In average-risk persons, the interval between screening examinations can be safely expanded beyond 5 years, provided the initial examination is a carefully performed complete colonoscopy that is negative for colonic adenomas or cancer.

Neuronal activity in nucleus ambiguous during deglutition and vocalization in conscious monkeys.

Extracellular recordings were made from the nucleus ambiguous in three conscious Macaca nemestrina monkeys during spontaneous vocalizations and swallows. The temporal relationship of neuronal activity to swallowing was inferred through correlation with the thyroarytenoid electromyographic (EMG) activity. Videofluoroscopic analysis of a fourth monkey during swallows of barium-impregnated fruit juice established the temporal relationship between swallowing and thyroarytenoid EMG activity. Of 691 cells recorded from the nucleus ambiguous and its adjacent area, the neuronal activity of 80 cells showed modulation during swallowing. Sixty-two cells were classified as "active" cells, with increased activity in relation to swallowing, while 18 cells were classified as "suppressed" cells, with tonic activity that reduced with swallowing. A continuum of latency was seen between the onset of modulation of these cells and the onset of swallowing, from "early" before the swallow to "late" after the swallow onset with most of the cells (44 cells) showing modulation near the onset of the swallow. A majority (37) of the 62 active swallowing-related cells also discharged with vocalization, but they demonstrated a lower discharge frequency and a longer burst duration during swallowing. Of the 18 suppressed swallowing-related cells, 11 cells discharged phasically with the respiratory cycle and may be a part of the ventral medullary respiratory center. This chronic awake primate model would preserve the many sensory inputs that may modify the oropharyngeal swallow and may better approximate human physiology.